Archiv für den Monat: März 2021

White Light equals Brown Noise

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Here is a recent show­er thought:

It is usu­al­ly said that the col­ors of noise are inspired by the spec­tral dis­tri­b­u­tions of cor­re­spond­ing col­ors of light. For exam­ple, the ‘white’ in white noise is an allu­sion to white light which is thought to have a (most­ly) flat spec­trum. But is this so? How does white light actu­al­ly look like, as an elec­tro­mag­net­ic wave?

So I made fol­low­ing fig­ure which shows some pow­er-law dis­tri­b­u­tions in the vis­i­ble range of wave­lengths col­ored by their the­o­ret­i­cal appearance:

Fig 1: Spec­tral dis­tri­b­u­tions with expo­nents from 0 to −4.

The col­or of the flat line is also known as Stan­dard Illu­mi­nant E‍‍ – or equal-ener­gy white light. Com­pared to the D65 white back­ground it has a rather pink­ish appear­ance with a cor­re­lat­ed col­or tem­per­a­ture of about 5500 K.

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Spotify Performance

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Just a quick post to report on my find­ings of mea­sur­ing the ener­gy impact of three dif­fer­ent ways to have Spo­ti­fy play­ing in the back­ground: the Spo­ti­fy app and the web play­er using two dif­fer­ent browsers (Safari and Fire­fox).

Inspec­tion of the pack­age con­tents of the desk­top app reveals it to be just a con­tain­er ver­sion of the web play­er, bring­ing with it its own instance of a Chromi­um Embed­ded frame­work (for a whop­ping 168 MB, no less). So what we are real­ly see­ing is the per­for­mance of the web play­er in three dif­fer­ent brows­er engines.

So here are the num­bers, tak­en from the ‘ener­gy’ tab in Activ­i­ty Mon­i­tor, on a Mac Book Pro 15″ (2017), and in all cas­es the win­dow was invis­i­ble off-screen*. I also includ­ed iTunes play­ing a local file for comparison:

idle play­ing
Web play­er in Safari 14.0 < 0.1 2.1
Web play­er in Fire­fox 86 < 0.1 13.8
Spo­ti­fy App 1.1.53 (Chromi­um embedded) 2.3 3.4
iTunes 12.9 < 0.1 1.7

(*the respec­tive app was first expand­ed full screen, and then the focus was switched back to the desk­top so that the app win­dow was total­ly not shown, not even a min­i­mized win­dow or icon)

And the win­ner for run­ning Spo­ti­fy with the least ener­gy impact is actu­al­ly the Safari brows­er. Con­grat­u­la­tions to the Apple engi­neer­ing team! The desk­top app run­ning Chromi­um Embed­ded comes sec­ond (but with a curi­ous­ly high idle activ­i­ty), while Fire­fox only comes last.

In the hope that this infor­ma­tion was use­ful, make of it as you will :)

EDIT: I just learned that the web play­er does not sup­port loud­ness nor­mal­iza­tion so it is not even an apples-to-apples comparison!